The esophagus is a hollow muscular tube that transports saliva, liquids, and foods from the mouth to the stomach. When the patient is upright, the esophagus is usually between 25 to 30 centimeters in length, while its width averages 1.5 to 2 cm.

The muscular layers that form the esophagus are closed tightly at both ends by sphincter muscles, to prevent food or liquids from leaking from the stomach back into the esophagus or mouth. When the patient swallows, the sphincters temporarily relax to allow passage of the food through.

The esophagus passes close to the trachea (breathing tube) and the left side of the heart. This means that problems with the esophagus, such as eating something too hot, can sometimes feel like a pain close to or in the heart or throat.

Like any other part of the body, the esophagus can be damaged. Heartburn and cancer are both problems affecting the esophagus. The most common problem is gastroesophageal reflux disease (GERD), when the sphincter at the base of the esophagus does not close properly, allowing stomach contents to leak back into the esophagus and irritate or damage it over time. With prolonged GERD, esophageal ulcer is likely to occur.